This section is intended to provide a background or context to the disclosed embodiments that are recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
Digital watermarks have been proposed and used for copyright protection of signals such as audio, video, images and the like. In a typical watermarking scenario an auxiliary information signal is hidden within a host content in such a way that it is substantially imperceptible, and at the same time, difficult to remove without damaging the host content. The auxiliary information that is hidden within the host content can then allow content management to be carried out to varying degrees. In some embodiments, content management includes, but is not limited to, the management of the use of content in accordance with one or more policies. For example, the auxiliary information may merely convey that the host content is not allowed to be copied (i.e., a “no copy allowed” watermark). Once extracted and interpreted by a compliant device, copying of the content is prevented. A compliant device can include, but is not limited to, a device that performs screening, or otherwise operates in a manner consistent with a content use policy. Content use (or the uses of content) can include, but is not limited to, operations involving content such as playback, copy, record, transfer, stream, or other operations. Additionally, or alternatively, the embedded auxiliary information can identify the rightful owner(s), author(s) and/or author(s) of the content or can provide a serial number associated with the content or other content identifying information. The auxiliary information can also be used for other applications, such as to monitor the usage of the embedded host content, resolve ownership disputes, and keep track of royalties and the like.
In order to extract and utilize the watermarks embedded in various content, substantial resources such as CPU cycles, digital memory, and communication resources may be engaged. This, in turn, can delay access to the content, increase the cost of manufacturing devices that are designed with a minimum processing load objective, increase battery consumption in mobile devices, etc. The processing burden associated with extracting such watermarks is often exacerbated by a need to perform certain additional content transformation operations, such as decryption, decompression, de-multiplexing, etc., that are must be performed before watermark extraction can be attempted.